1. Field of the Invention
The invention relates to a conveyor for use in a reaction chamber and is particularly useful when used in a fluidised bed reaction chamber, such as is used in the roasting or drying of granular material such as coffee beans, peanuts, wheat etc.
2. Description of the Prior Art
European Pat. No. 63486 describes a fluidised bed reaction chamber in which a conveyor effectively divides the reaction chamber axially into separate zones and acts to move a dose of material successively from one zone to the next after a period of dwell in each zone. The conveyor comprises a plurality of discs spaced axially along a shaft and mounted for rotation with the shaft to provide a plurality of substantially separate zones between the discs. The conveyor co-operates with a chamber wall which has a part-cylindrical portion closely surrounding at least the lower part of the discs. Material is conveyed from one zone to the next through openings in the discs and each opening is associated with a transfer blade extending across the respective zone to urge material through the opening as the conveyor is rotated.
In the previously known conveyor each disc is provided with a single opening for passage of material therethrough and the openings in successive discs are axially aligned with one another or are successively equally circumferentially displaced such that the dwell time of material in each zone is the same and each dose of material is moved stepwise along the conveyor from one zone into the next successive zone.